The present invention relates to a separation device for a vacuum cleaner having a vacuum source which, via a tube connection, communicates with a tube handle, and wherein the tube handle is connected to a nozzle by means of a tube shaft.
Vacuum cleaners of the type mentioned above, so-called canister vacuum cleaners, are previously known. These vacuum cleaners comprise a vacuum cleaner housing having a vacuum source, usually a fan unit, and a dust container or bag. The dust particles entrained in the air drawn through the nozzle flow through the tube shaft, the tube handle and the hose into the air-pervious dust bag in which the particles are collected before the filtered air flows further through the fan unit to atmosphere.
It is previously known to use separating devices for canister-type vacuum cleaners in order to separate larger dirt particles before they reach the dust container. Such a device is described in DE-A-2946572. This publication shows a canister-type vacuum cleaner in which the cyclone separator is placed directly on the vacuum cleaner housing. The outlet of the separator communicates with the dust container, whereas the vacuum cleaner hose is connected to the separator. However, the position of the separator has certain disadvantages since it increases the total height of the vacuum cleaner housing, which means that tensioning forces, which always are present in the hose when the vacuum cleaner housing is moved on the floor, are applied to the vacuum cleaner at a high level and, hence, cause undesirable turning moments on the separation device and on the vacuum cleaner. Thus, the fastening means of the separation device has to be designed to resist these moments and forces. The high position at which the forces are applied also means that the vacuum cleaner has a tendency to tip-over when it is moved sideways.
It is also previously known to use cyclone separators in so-called upright vacuum cleaners. See, for instance, EP-A-489565. Upright vacuum cleaners are, however, designed quite differently than canister cleaners since the nozzle and the vacuum cleaner housing is one single non-separable unit in which also the cyclone separator is placed.
U.S. Pat. No. 5,350,432 describes a canister-type vacuum cleaner having a tube shaft in which the air is circulated during its upward movement within the shaft. The circulating flow is created by means of an element provided with inclined vanes that is placed within the tube shaft. A dirt collecting chamber communicating with the tube shaft by means of a small opening with a cut piece is placed at the upper end of the shaft. The '432 arrangement is complicated and, since the tube shaft is mainly directed upwards, during handling there is a risk that particles which have been sucked into the tube shaft are not lifted up to the opening to the collecting chamber but rather fall backwards within the shaft.